Synchronizing update of time of day counters using time stamp exchange over a control plane
AssigneeSkyworks Solutions, Inc.
InventorSrisai Rao Seethamraju
Life of this patent
Estimating the term…
Abstract
A control plane, available to all of the line cards in a system, is used to exchange time stamps to align the Time of Day counters in the master line cards. The master line cards are locked to a system clock distributed over the backplane by a timing card. The timing card is locked to timing of a slave line card that is synchronized with the grand master. Each master line card synchronizes updating its Time of Day counter based on a time stamp exchange and a local clock locked to the system clock and without the use of a 1 pulse per second signal.
Claims20
A method for synchronizing time of day counters comprising:
- synchronizing a first time of day counter on a slave line card to grandmaster timing;
- synchronizing a second time of day counter on a first master line card to the first time of day counter on the slave line card based on a first time stamp exchange between the slave line card and the first master line card;
- performing a second time stamp exchange between the first master line card and a second master line card;
- and
- synchronizing a third time of day counter in the second master line card to the second time of day counter in the first master line card based on the second time stamp exchange between the first master line card and the second master line card while the first master line card maintains synchronization with the slave line card.
An apparatus that synchronizes time of day counters comprising:
- a slave line card with a first time of day counter synchronized to grandmaster timing;
- a first master line card with a second time of day counter synchronized with the first time of day counter on the slave line card based on a first time stamp exchange between the slave line card and the first master line card;
- and
- a second master line card configured to perform a second time stamp exchange with the first master line card, the second master line card including a third time of day counter synchronized with the second time of day counter in the first master line card based on the second time stamp exchange between the first master line card and the second master line card while the first master line card maintains synchronization with the slave line card.
Dependencies are inferred from the claim text.